Drafting-rule.



gNo. 709,776. Patented Sept.: 23, |902.

M. c, KELLEY. DRAFTING RULE.

fgpplication med Jan; 1, 1902.)

(no Model.)

llNTTnn dTaTns ldaTnNT @Trient MARY C. KELLEY, OF IVILMINGTON, DELAWARE.

DRAF'I'IINGRULE.

SPECIFICATION forming part Of Letters Patent No. 709,776, dated. September 23, 1902.

Application led January 4, 1902. Serial No. 88,429. (No model.)

To @ZZ whom, it may concern:

Be it known that I, MARY C. KELLEY, a citizen of the United States, residing at IVilmington, in the county of Newcastle and State of Delaware, have invented a new and useful Drafting-Rule, ot which the following is a specification.

This invention is an improved drafting-rule, the object being to provide an exceedingly cheap and simple appliance by means of which a multiplicity of diiterent figures-plain, curvilin ear, and miXtilineal-can be quickly and easily constructed.

With these various objects in view the invention consists in the peculiar construction and arrangement of the several parts hereinafter fully described, and pointed out in the claim.

In the drawings forming part of this specification, Figure l is a face view of a draftingrule constructed in accordance with my invention. Fig. 2 is an edge view of the same.

In constructing a rule in accordance with my invention I may make the same from a thin metal plate,sheet of celluloid,pasteboard, or from thin veneer of wood.

The device comprises a body A and an arm B, extending from one end of said body portion A. The end of the body portion is cut straight or, rather, upon an incline, as most clearly indicated at A. The edge A2 of the body is a straight edge and may be subdivided according to any particular scale. The opposite edge of the body, as indicated at A3, is curved, said curve constantly changing or varying, so that along this edge a multiplicity of different arcs can be made. The body portion A is preferably cut out as shown at A4, one edge A5 being straight and the opposite edge AG being curved, said edges A5 and Ai intersecting at A7. The arm B has a V-shaped notch B/ cut in its end. Should it be desired to ascertain whether two or more points. are the same distance from a central shaft, the notch B will fit approximately over the shaft, and the rule may be moved around it from one point to the other without slipping. Both edges of the arm B are graduated upon the same scale as the curved and straight edges of the body portion A. Between the points l and 2 the outer edge of the arm B is struck upon the arc of a circle Whose center is 3. Between the points t and 5 the inner edge of' the arm B is struck upon a circle whose center is 6. It will be noted that the point 4t is at the intersection of the straight edge A2 and the arm B. The remaining portions of the curved edges of the arm B are variable curves. One or both sides of the rule may be provided with scales or graduations, as preferred. The simplicity of the device is apparent to every one, and owing to the peculiar arrangement of' the straight and curved edges and by having curved edges which form considerable portions of circles I ain enabled to produce a great variety of different designs or patterns.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

A device of the kind described, comprising a body portion and a curved arm, the end of said arm being bifurcated, one edge of the body portion being a straight edge, the other edge being a constantly-varying curve, one edge of the curved arm containing a long arc of a circle, the other edge ot' the curved portion containing a short arc of a circle, said short arc intersecting the straight edge of the body portion, substantially as describedn MARY C. KELLEY.

Witnesses:

WILLIAM LILE, LUcIoUs C. JONES. 

